In the past pharmaceutical composition of a similar kind have been used in the form of solid suppositories having an oil or fat base, or as liquid agents. However, liquid agents are apt to flow out or be excreted from the body after insertion and the pharmaceutical ingredient is not sufficiently absorbed in the body. A suppository is a pharmaceutical composition which is solid at room temperature, wherein a pharmaceutical ingredient is contained in a base composition, such as cacao butter, which melts gradually under body heat. Such a composition requires a long time for melting in the body, during which time a film of the base composition is formed on the mucous membrane of the body, and the absorption of the pharmaceutical ingredient into the body is suppressed, thus curtailing the medicinal effect. A suppository must be kept at low temperatures so as to preserve a fixed shape and maintain a sufficient solidity when inserted into the body. Also, a suppository gives an uncomfortable feeling to the patient at the time of insertion, it is difficult to insert, and when inserted into the rectum it maybe excreted in the original state. Thus, the suppository has been not only inconvenient in its use but also insufficient in its medicinal effect.
On the other hand, pharmaceutical compositions having been commonly administered by injecting into the body. Injection is an effective method for providing a desired concentration in the blood and realizing a medicinal effect, but it may give rise to a nerve disturbance, especially contraction of muscle tissue such as a contraction of quadriceps femoria muscle. For this reason, administration by injection has come to be strictly restricted.
In an attempt to obtain a pharmaceutical composition which can provide sufficient medicinal effect and can be administered safely in suitable dosages, the present inventor conducted strenous study and found that a pharmaceutical composition, comprising a gel form base composition having a specific viscosity based on a carboxyvinyl polymer impregnated with a pharmaceutical ingredient, has excellent properties when compared with the conventional suppositories and fully satisfies its intended medicinal purpose.